Improvement in truss-bridges



` rection;

PATENT OFFICE.

A. MCGUFFIE, OF ROCHESTER, NEW YORK..

IMPROVEMENT JN TRuss-BRIDGES.

Specification forming part of Letters Patent No. 35,381, dated May 27, 1862.

ester, in the county of Monroe and State of New York, have invented a new and useful i Improvement inTruss-Bridges; andIdo here- Y by declare that the following is a full, clear,

and exact description of the same, reference being had to the accompanying drawings, making a part of this specification, in which- Figure 1 is a longitudinal vertical section of a bridge constructed according to my invention. lFig. 2 is a plan of the same, partly in section. Fig. 8 is a transverse vertical secr tion of the same at the center of the span.

Similar letters of reference indicate corresponding parts in the several gures.

This invention consists in a novel arrangement and combination of wooden arch segments, posts, and chords, and wrought -iron angle-braces, forming a very simple, strong, and stiff truss.` 4

To enable others skilled in the art to construct bridges according to my invention, I will proceed to describe it with reference to the drawings.

A A are the straight timbers forming the lower chord ofthe truss.

B B are the arch sections, composed of straight timbers forming an arch by abutting together in the manner shown at a a in Figs. 1 and 2, where they are secured by bolts b b to posts C C, which connect them with the lower chord, the connection of the said posts with the lower chord beingby means of bolts c c passing through them, the posts being notched between the chord-timbers A A and received between the two or more parallel series of timbers, B B. Thearch is stiffened laterally by blocks dd, introduced between the timbers A, and these blocks `with the posts may give sufficient stiffness ina lateral divbut I prefer in a truss in which several series of timbers A A are used, as shown in the lower side of Fig. 2 and left-hand side of Fig. 3, to have the inner series of timbers, A A to break joints with or lap the outer ones, as indicated at e e, in Fig. 2, the right hand half of which represents a horizontal section below the upper chord. Bolts f f are inserted through the timbers B B at the intersections of the blocks d d. The end timbers A A are notched to the lower chord-timbers and bolted to said timbers and-to the end posts, as shown at c c' in Fig. l, and one or more of the said timbers at each end of the truss are extended through the lower chord and have ltheir feet shod with cast-iron shoes I I, to bear upon the abutments or piers of the bridge.

D D are angle-braces, of wrought-iron, for bracing the arches. These may be connected with the arch at its intersection with the posts either by means of inverted stirrups g g and nuts hh, as shown in Fig. l, or by means of blocks applied between the posts and nuts appliedabove the. said blocks. They are con nected with the lower chord by means of blocks E E, notched into the bottom of the lower chord at the feet of the posts and nuts it', applied under the said blocks. Thesaid braces run from the intersection of one post with the upper chord to the foot of the next post ou either side of it. These braces operate in combination with the posts and the lower chord to brace the arch.

F F are the top chord-timbers arranged horizontally and parallel with the lower chord and united with the posts by being notched to them and by bolts j j, inserted through them.

G Gr are diagonal wooden braces for keeping apart the upper chords of the two trusses of which the bridge is constructed and stiftening the bridge laterally.

H H are tension-braces applied to the two top chords.

The cast-iron shoes I Lfitting to the feet of the end timbers B B of the arch may be secured by bolts passing through them, and may also be further secured by means of straps g' g and rods D D', applied `to serve at the same time a purposeA substantially similar to the stirrups g g and angle-braces D D. These shoes, resting on the abutments, relieve the bottom chord of pressure and of all strain but a tensional one and throw all the weightof y the bridge on the arch.

What I claim as my invention,and desire to secure by Letters Patent, is-

The truss composed of the archseetions B with their shoes I I to rest on the abutments or piers, the chords A A and F F, posts C C, and angle-braces D- D, the whole arranged and combined substantially as and for the purpose herein specified.

A A. MOGUFFIE. Witnesses:

I. H. ELLIS, H. MGGUEEIE. 

